The present invention relates to blade mounting in a bulldozer tractor.
Heretofore, blade mounting in a bulldozer tractor has been proposed in which a pair of push arms are pivotally mounted at their proximal ends on the opposite sides of the tractor by means of trunnions and a bulldozer blade is pivotably connected at its back to the distal ends of the arms at the respective ends of the blade and a tilt brace is provided extending between the top of each of the arms and the rear upper side of the blade at the respective ends thereof for tilting the blade around the longitudinal axis of the tractor. In such a type of the blade mounting, when a force is applied to the blade laterally of the longitudinal axis of the tractor, the blade is swung laterally of the tractor thereby resulting in breakage of the arms. In order to prevent the breakage of the arms caused by the force applied to the blade laterally of the tractor, a pair of diagonal braces are provided which are swingably mounted on the respective arms and extend inwardly toward each other with the inner ends being pivotally joined so that the lateral swunging movement of the arms is prevented by virtue of the connection of the inner ends of the diagonal braces. However, the provision of such diagonal braces obstructs the tilting operation of the blade around the longitudinal axis of the tractor.
In order to avoid the above disadvantage of the blade mounting in the prior art, a blade mounting has been proposed as disclosed in U.S. Pat. No. 3,395,764 in which each of the diagonal braces comprises a first strut pivoted to the respective arm and extending parallel to the blade and a second strut pivoted to the respective arm rearwardly of the first strut and converging forwardly to join the first strut centrally of the blade, the inner ends of the braces are joined by slidable and universally adjustable means which is also loosely connected to the back of the blade. With the arrangement of the blade mounting as described above, the stresses generated during the tilting of the blade are evenly distributed in various elements so as to prevent breakage of the elements while the tilting is freely effected and the arms are reinforced to avoid the breakage thereof by the diagonal braces when a force is applied to the blade laterally of the tractor. However, in such a construction of the blade mounting, slidable and universally adjustable connecting means is required for joining the inner ends of the diagonal braces which is also loosely connected to the back of the blade thereby requiring a large number of elements resulting in time consuming assembly and disassembly of the blade and high cost in manufacture of various elements while the elements are subjected to wear due to slidable connection between various elements.
The present invention aims at avoiding the disadvantages of the prior blade mounting in a bulldozer tractor as described above.